Biological Sciences Division Research Highlights

Data may help harness microbes to produce green fuels

Results: Garbage in, fuel out? Scientists at Pacific Northwest National Laboratory designed and built a novel bioreactor that may shed light on how to convince microbes to convert or metabolize municipal garbage into biodiesel and other fuels. The bioreactor offers accurate, detailed data on chemicals produced by the microbes without sampling. Further, this technology allows frequent measurements without diminishing the sample, and it is compatible with other analyses.

Why it matters: Sampling stresses microbes. When they are stressed a cavalcade of undesired chemical changes occurs that may be irrelevant to the conditions being studied. The MRI bioreactor allows noninvasive, real-time measurements of the chemicals produced, intermediates formed and byproducts. Understanding metabolite concentrations, metabolic pathways and flux rates under a range of known conditions is necessary to optimize processes that use microbes to convert municipal wastes, forest litter and other feedstock into biodiesel, ethanol, butanol and other fuels, advancing the scientific frontiers to reduce the nation's dependence on imported oil.

Methods: The bioreactor uses noninvasive nuclear magnetic resonance imaging and spectroscopy (MRI/MRS) methods, similar to a hospital's MRI, to monitor microbial metabolite concentrations in the reactor. The first investigation performed in the bioreactor was a study on the anaerobic metabolism of Eubacterium aggregans, a bacterium of interest for biofuel production. The study showed that in addition to known metabolic byproducts, E. aggregans produces significant concentrations of lactic acid, a result not previously reported in studies using conventional experimental techniques.

What's next? The research team plans on developing the new bioreactor to look at cyanobacteria or blue-green algae, which are of interest for energy production and carbon sequestration.

Acknowledgments: This work was funded by the Laboratory Directed Research and Development Program at PNNL. The work is part of the national laboratory's contributions to developing and deploying transformational tools and techniques for the biological, chemical, environmental, and physical sciences.

The research was conducted by Paul Majors, Jeffrey McLean, and Johannes Scholten of PNNL. The work was performed in the U.S. Department of Energy's EMSL, a national scientific user facility at PNNL.

Citation: Majors PD, JS McLean, and JC Scholten. 2008. "NMR Bioreactor Development for Live In-Situ Microbial Functional Analysis." Journal of Magnetic Resonance 192(1):159-166. Artwork from this article was featured on the cover of the journal.